Question

If 0.9x - 1.3 = -3.1, what is the value of x - 0.8?

Answer 1

Answer:

\begin{gathered} {0.9x}^{2} - 1.3x = 0.8x - 1 \\ \\ {0.9x}^{2} - 1.3x - 0.8x = -1 \\ \\ {0.9x}^{2} - 2.1x = - 1 \\ \\ {0.9x}^{2} - 2.1x + 1 = 0 \\ \\ {0.9x}^{2} + 1.5x + 0.6x + 1 = 0 \\ \\ 1.5x(0.6x+1) + 1(0.6x + 1) = 0 \\ \\ (0.6 + 1)(1.5x + 1) = 0\end{gathered}

0.9x

2

−1.3x=0.8x−1

0.9x

2

−1.3x−0.8x=−1

0.9x

2

−2.1x=−1

0.9x

2

−2.1x+1=0

0.9x

2

+1.5x+0.6x+1=0

1.5x(0.6x+1)+1(0.6x+1)=0

(0.6+1)(1.5x+1)=0

Now,

x = \frac{ - 1}{0.6} \: or \: \frac{ - 10}{6}x=

0.6

−1

or

6

−10

Also,

x = \frac{ - 1}{1.5} \: or \: \frac{ - 10}{15}x=

1.5

−1

or

15

−10